Concrete cracks in intertidal zones deteriorate faster due to seawater dry-wet cycles. Researchers studied how cracks change under these conditions. They took concrete crack samples, exposed them to seawater, and scanned them after different cycles. Results showed that cracks in seawater deteriorate in two stages: first, chemicals from seawater erosion dominate, then erosion and flaking from dry-wet cycles take over. Changes in crack surface shape were more significant with higher seawater concentrations.